NASA discovery puts life on Mars "on the table"
NASA scientists found evidence on Mars that suggests ancient life could have existed on the planet, providing "a piece of the Mars puzzle that scientists have long been seeking," per the New York Times. Specifically, scientists found organic matter in rock fragments that formed billions of years ago.
But, but, but: This isn't direct evidence of life itself, NASA cautions. Per the Times, the carbon molecules discovered by NASA's Curiosity rover can be found in meteorites, and can be produced "in chemical reactions that do not involve biology."
The details: After heating the rock fragments "to more than 900 degrees Fahrenheit," the NYT reports, Curiosity identified molecules that "wafted away" due to the high temperature. Scientists then examined which molecules were "genuine Martian organics." The molecules that remained were benzene and propane.
- Scientists haven't pinned down how the molecules were formed, but are considering meteorites, biology and geology.
- The argument for biology — that is, live material on the planet — isn't supported by "compelling evidence," the NYT reports, but NASA biogeochemist Jennifer L. Eigenbrode told the Times it's "on the table."
Another finding was that methane levels in Mars' atmosphere have gone "up and down by a factor of three...and appear to follow Martian seasons," per the Times.